Such electronic apparatuses as a communication apparatus and an electronic voice recording pen have been widely used till now. Such the electronic apparatuses collect voice signals of users via microphones, convert the voice signals into digital signals for transmission and/or recording, and then play them. In collecting voice signals of the users, ambient noises may be mixed into the microphones, thereby preventing the voices from being heard.
In the relevant art, multiple filtering technologies have being developed, which may improve the quality of the collected voice signals by lowing the levels of the noise signals and keeping or improving the levels of the voice signals.